This invention relates to electronic musical instruments having automatic performance functions, and more particularly to tone production control when an automatic performance is temporarily suspended in such an electronic musical instrument.
Known in the art is an electronic musical instrument having automatic performance functions in which an effect like arpeggio is automatically realized by producing successively, one after another, at suitable time intervals tones concerning one or plural keys in the keyboard. In this automatic arpeggio performance, the tones thereof are automatically produced one by one in a percussive mode at desired time intervals. The term "percussive mode" used herein is intended to mean a mode in which an envelope of each produced tone decays with time immediately after a rising portion of the envelope.
Furthermore, known in the art is an electronic musical instrument having as its automatic performance functions an automatic bass/chord performance function and an automatic rhythm performance function. In the case where a chord is automatically performed with the electronic musical instrument of this type, a key or plural keys in a chord are depressed in the keyboard and the chord name is automatically determined from the key or the combination of the keys depressed to specify the tones to be produced, and furthermore tones are produced as bass tones one by one according to a desired bass pattern with tones corresponding to the root note and subordinate note of the chord. The term "subordinate-note" used herein is intended to mean a note having a predetermined note interval (first, major second, minor third, major third, etc.) with respect to the root note. The bass pattern is determined in correspondence to a desired rhythm pattern selected by a performer. In this operation, the specified tones are controlled so as to be simultaneously produced as an automatic chord, tone for every suitable timing corresponding to the aforementioned rhythm. Furthermore, the automatic rhythm tone is produced in correspondence to the selected rhythm, as a result of which the automatic bass tone, the automatic chord tone, and the automatic rhythm tone are produced in combination, whereby the automatic performance is carried out. Generally these automatic performance tones are produced in an intermitent mode which is intended to mean a mode in which a tone or tones are produced intermittently one by one or all together with predetermined time intervals.
However, it is very inconvenient for the electronic musical instrument having the various automatic performance functions described above that when the automatic performance functions are stopped, tones immediately stop producing as a necessary consequence in spite of continuous depression of the key or keys. As a result, interest in playing the electronic musical instrument may be greatly reduced. In addition, since key depression is effected in the automatic performance, it is considerably inconvenient to stop the automatic performance by hand.
In the case where the automatic performance is stopped, or in the case where the automatic performance is switched over to the manual performance, it is desirable to continue the tone production and further, to change the tone production mode to a sustaining mode and a continuous mode. The terms "sustaining mode" and "continuous mode" used herein are intended to mean a mode in which an envelope of each produced tone is sustained with a substantially constant level after a rising portion of the envelope and a mode in which a tone or tones are produced continuously one by one or all together, respectively. Thus the manual performance can smoothly follow the automatic performance with a clearly distinguishable difference in the tone production mode giving an attractive effect to a sound.